This invention relates to cogeneration associated air conditioning wherein the working fluid is a hygroscopic (i.e. desiccant) solution and wherein the moisture concentration is processed by a desiccant regeneration unit serving a multiplicity of contactors (i.e. units) or dehumidifiers. Heretofore, the regenerator and contactor units have been balanced so that the capability of the former meets the demand of the latter. That is, the desiccant regenerator unit and contactor unit have been selected for compatability one with the other. Therefore, these complementary units have been selected for peak load conditions, and they have not been used to their ultimate effectiveness during moderate or low load conditions, nor has either unit been effectively used during no load conditions. It is therefore an object of this invention to advantageosuly employ a multiplicity of space air handling units in a system characterized by at least one central service system, and preferably a service system which features a single regenerator unit for regenerating the hydroscopic solution and which supplies a multiplicity of contactor units preconditioning outside or mixed outside and return air, and wherein each contactor unit can service one or more cooling coils for sensible heat absorbtion in space air distribution means.
Air conditioning systems of the type under consideration have employed the direct cooperation of desiccant regenerators and dehumidifying contactors supplied with concentrated desiccant therefrom. In fact, these two units are often combined as a single apparatus having a common sump, in which case the capacity of one matches the other. With the present invention, the capacity of the regenerator unit is deliberately selected to meet the contactor unit, or units, requirements for a total work output per period of time. That is, the regenerator capacity for a total 24 hour day of maximum requirement can be selected, whereby said regenerator unit is operated at full capacity on a continuing basis; except for shutdown when air conditioning is reduced or is terminated. Accordingly, it is an object of this invention to provide for storage of the working desiccant fluid processed by the continuously operating regenerator unit. With the present invention, a working fluid storage tank accumulates the desiccant fluid processed by the regenerator unit for subsequent use by the multiplicity of contactor units.
The central desiccant regenerator unit (preferably but one but in some instances more than one) requires heat application for its operation, and to this end the waste heat of combustion from a prime mover of the heat engine type is employed on a continuous basis for a defined operating period of time. Accordingly, it is an object of this invention to combine an electrical cogeneration unit with the air conditioning regeneration unit for its continuous operation during defined operating period, both at full or substantially, cost effective, full capacity.
By continuous operation, it is meant that the regenerator, being undersized so to speak is chosen for peak coincident moisture load for the multiplicity of contactor units in service, is required to operate at or near its rated capacity for extended periods of time, such that it is capable of removing the same pounds of moisture per operating day that a so called full sized regenerator might provide if operated in the normally accepted manner to meet the varying instantaneous moisture loads.
The storage tank which characterizes this invention can be a singular tank for averaging the strength of the desiccant, or it can be separated into a first stage receiver tank of weakened desiccant fluid, and a second stage supply tank of strong regenerated desiccant fluid. It is an object of this invention to separate the storage of the hydroscopic desiccant fluid so that the weakened returned desiccant fluid is not commingled with the strengthened desiccant that has been regenerated for use in the multiplicity of contactor units. With the present invention, there is a receiver tank that receives weakened desiccant discharged by the contactor units, and holds the same for supplying the regenerator on demand. And there is a supply tank that accumulates strengthened desiccant from the regenerator unit and holds the same for supplying the contactor units on demand.
The processed desiccant fluid stored in the working fluid storage tank or tanks is supplied to the multiplicity of contactors for conditioning of air supplied by evaporative chilling and preferably by a single indirect evaporative chiller within the central support system. A feature and an object of this invention is to advantageously employ the circulation of chilled water to and/or from cooling coil units, by directing the same through automatic fire sprinkler mains and thereby continuously purging the same on a full time basis.
Contactor unit operation requires chilling, and to this end it is an object of this invention to provide a single indirect chiller within the central support system. With this invention there is an indirect evaporative chiller that supplies the cooling coils of a multiplicity of contactor units.
From the foregoing it is apparent that a general object of this invention is to separate an air conditioning installation into a continuosuly operating support and total dehumidification system and a demand operated sensible cooling air handling system. The support system is characterized by a generator unit or units operating on a cost effective full time basis, or substantially so, and by storage of desiccant fluid processed thereby, and preferably supported by a congeneration electrical generator unit also operating on a cost effective full time basis. The air handling system is characterized by a multiplicity of contactor units operated on demand and supplied with processed desiccant fluid from the aforesaid storage as circumstances require. The air handling system includes a multiplicity of air handling units that have cooling coils associated with a refrigeration unit, an evaporation or mechanial chiller, and a cooling tower as shown and described. And the air handling units have heating coils associated with a water heater or boiler also drawing waste heat from the cogeneration prime mover.